Metabolic engineering of Aspergillus niger to enhance production of ethanol

This work describes the genetic transformation of a strain of Aspergillus niger with five different constructs containing 16 different heterologous genes coding for four oxidoreductases, two cellobiohydrolases, one endoglucanase, one β-glucosidase, six enzymes involved in xylose metabolism and two enzymes involved in fermentation. The aim was to try and engineer a consolidated bioprocessing in A. niger. The fungus already contains most of these enzymes and we only enhanced endogenous activities. We recovered nine transformants containing all genes, as indicated by PCR. To confirm that the products of the genes were functional, we measured the activity of five different enzymes in all the strains and they all showed enhanced activity over the wild type [wt] strain. The strains were grown on CMC and xylan as substrates and they produced considerably more ethanol than the wt. The levels of ethanol production were comparable to those reported in the literature. Aspergillus niger was transformed with four oxidoreductases, two cellobiohydrolases, one endoglucanase, one β-glucosidase, six enzymes involved in xylose metabolism and two enzymes involved in fermentation from different fungi with the aim to enhance ethanol production. Several enzyme activities related to lignocellulose hydrolysis were markedly enhanced as a result of the transformation. This article is protected by copyright. All rights reserved.